A liquid crystal display device is a type of a display device. A liquid crystal display device in which a plurality of pixel electrodes are driven by thin film transistors, respectively, is known. Such a configuration is called an active matrix type. This liquid crystal display device includes gate wiring lines disposed on a substrate for supplying signals to thin film transistors, and a plurality of source wiring lines formed above the gate wiring lines so as to intersect with the gate wiring lines.
Japanese Patent Application Laid-Open Publication No. 2008-277371 (Patent Document 1) discloses an example of the invention for preventing disconnections of the electrode material in forming thin film transistors in a display device of the active matrix type.